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You’ve bought an iTechworld inverter generator with built-in 12-volt outlets. But how do you go about charging 12v batteries from your generator? Here’s a quick rundown of what you need to know.

Let’s get straight to point: Most inverter generators may have a 12-volt output on them, but when it comes to the crunch, they are not designed to fully charge your batteries directly. There are two main reasons why:

First, your generator’s DC outlet is limited to a current of about 8 amps maximum. So any battery will take a while to fully charge.

Secondly, the voltage of the DC output isn’t regulated – it varies according to the generator’s RPM. This is fine if the generator is running a low load, but not if it’s running a medium to high load. Also, the generator won’t cut back the charge when the battery is nearly full, so you can’t risk leaving it charging for too long.

The bottom line: Your DC output on your generator is best for emergency or short term charging, i.e. providing your car battery a trickle charge. Anything more is a potential risk to your batteries.

So what’s the solution?

The best way to charge your battery is to run the iTechworld 20 Amp 240-volt battery charger off the generator’s AC output. This will recharge the battery much faster and accurately. Putting in a hefty 20 Amps. Also, the iTechworld 20 Amp 240-volt battery chargers regulate themselves down, so as charge builds in the battery, the charger won’t be pushing the same amount of amps. It will also cut off when the battery is fully charged.

So as a backup or alternative to your solar set up to charge your camping/caravan/motorhome battery packs, iTechworld Generator Inventors are a great option when they are working with the iTechworld 20 Amp 240-volt battery charger, especially as you can also run your appliances on 240v straight from the generator also.

How much solar power do you need?

So you want to set your rig up for Solar but you are not sure what size of set up you need? This blog is designed to give you the tools to be able to work out exactly what are you are drawing from your rig's batteries and what type of Solar set up you need. Knowledge is key when setting up your rig for Solar so the more information you have on each and every one of those home comforts devices you plan to take away with you the better. If anyone has a question pop it in the comment section below. I will answer each and everyone.

How to work out Watts, Amps and Volts

It stands to reason that a larger Solar Panel will collect more energy in less time, but just how big does the solar panel need to be?

The power consumption of appliances is given in Watts. To calculate the energy you will use over time, just multiply the power consumption by the hours of use. For example:

10 watt device used over 3 hours equals 10 x 3 = 30 Watt

How to convert Amps to Watts

The energy in Watts is equal to the electric charge in Amps times the voltage in volts:

Watts = Amps × Volts

Example

If your device doesn’t have the Watts labelled on it, then it should at least have the input Volts i.e. 240V and the Amps AC it draws such as 240V – 1.5A. You can then use the equation Watts Volts x Amps so 240v x 1.5amps = 360 Watts.

How to convert Watts to Amps

The electric charge in Amps is equal to the energy in Watts divided by the voltage in volts (V):

Amps = Watts / Volts

Example

Find the electric charge in Amps when the energy consumption is 300 watts and the voltage is 240 volts.

300 Watts / 240 volts = 1.25 Amps

Check out the iTechworld inline Watt meter which does all these calculations for you HERE

Do I need a battery?

Solar panels are commonly used to charge a battery – not to charge a device directly. There are a couple of reasons for having batteries. Solar panels might not generate enough wattage to directly power an appliance, but they can build up a higher wattage via a battery. Secondly a battery can regulate the power going in to the appliance at a constant rate. When solar panels are charging a battery it is usually at a varying rate which could harm an appliance if not regulated.

Battery capacity is measured in Amp Hours (e.g. 100Ah). You need to convert this to Watt Hours by multiplying the Ah figure by the battery voltage (e.g. 12V) – see calculations above.

AH refers to amp hours. This rating is usually found on deep cycle batteries. If a battery is rated at 100 amp hours it should deliver 5 amps of power for 20 hours or 20 amps of power for 5 hours.

When choosing a deep cycle battery, keep in mind the equipment you will be powering and the time in which they will be running. Theoretically a 100Ah battery can deliver 5 amps over a 20 hour period (and so on). Taking into account the average small campsite - with a small 45W fridge running for 6 hours, 3 hours of 15W lighting and 20W of other electronic equipment - the minimum consumption to be expected is 335W. Take this wattage and divide it by the voltage, 12V, gives 28Ah. With the aim of leaving 50% in the battery brings the requirement to 56 Ah per day.

Check out the only the battery that iTechworld recommends with Solar Power HERE

What size solar panel do I need?

Solar Panels power generation is commonly given in Watts e.g. 120 Watts. To calculate the energy it can supply the battery with, divide the Watts by the Voltage of the Solar Panel.

120 Watts / 18v = 6.6 Amps

Please note that Solar Panels are not 12v, I repeat Solar Panels are not 12v. Any one who works out the Amps of a solar panels using 12v as the voltage calculation does not understand solar or has been misinformed. All solar panel voltages should be marked in the item description of our website or on the unit itself.

The power inverter converts your storage battery power into the 240 volts AC that runs your appliances. Unless you only run 12 volt DC appliances you will need a power inverter to supply your AC.

There are 2 types of Inverters

Pure sine wave and Modified sine wave.

The Pure Sine Wave matches the power to that of which you get from your Electricity Supplier, its clean and you can run any appliances safely even sensitive equipment.

The Modified sine wave used to be considered a dirty power but some aren't as bad as they used to be, you can use this inverter type for things that don't have sensitive electronics for example fridges, cookers, pumps, You may have to be careful with some appliances such as laptops and TVs so check first.

All Solar Panels 30 watts and above need a Solar Charge Controller/Regulator. A Charge Controller/Regulator is necessary to protect the batteries from over charging and supply them with the proper amount of energy to promote long battery life. If the charge isn’t regulated it can have a damaging effect on the battery being charged.

Alternating current So, you’re looking to purchase an inverter to run an AC-powered device off a battery or other DC source. Will you need a pure-sine-wave inverter (PSW), or will a cheaper modified-sine-wave inverter (MSW) do the job?

To answer that question, let’s begin by looking at what AC is. For starters, it’s short for alternating current. In other words, it denotes a current that repeatedly changes direction. This goes for the output of both pure- and modified-sine-wave inverters. Both are AC. What sets the two apart, is how the current changes direction and how long it stays level. Have a look at the pictures below.

As you can see, the pure sine wave features a smooth, flowing rhythm. It’s similar to what you’d think of as a “wave”. Consequently, it’s also called a “true” sine wave. This is more or less what you get in your power point at home, and it is what most household appliances are designed to run on.

In contrast to this, the modified sine wave features prolonged highs and lows as well as plateaus at zero voltage, giving it a rather squarish look. Not surprising, then, that it’s also called a “square” sine wave.

Some appliances are compatible with a modified sine wave; others are not. As a general rule, the more complex the appliance, the likelier it is that it requires a pure sine wave. But to be absolutely sure, you should always go by what the manufacturer says. To give you a better idea of how the different waveforms affect different appliances, let’s have a look at the two waveforms in greater detail, though.

Modified-sine-wave inverters MSW inverters utilise filters to round the corners of a square wave; hence the word “modified”. As previously mentioned, however, the shape of the wave remains quite square.

Because of the plateauing peak outputs, appliances running on a modified sine wave will have to deal with more power for a longer time, and this equals additional heat. For this reason, many appliances that are designed to run on grid power will overheat if run on a modified sine wave.

Nevertheless, MSW inverters do have their place. Since they don’t require as many components as pure-sine-wave inverters, they are relatively cheap. And they typically use DC power more efficiently than PSW inverters, meaning that your battery will last longer. So, if you plan to run only normal light bulbs and induction or shunt motors, for instance, an MSW inverter will be the right choice for you. However, as previously mentioned, take heed: if you are unsure of whether your appliance will run on MSW, make sure of it before you plug it in.

Pure-sine-wave inverters Manufacturing a PSW inverter is a lot more involved than making an MSW inverter, and this translates into a higher price. But what you get for the additional cost is peace of mind. Appliances are getting increasingly complex; these days, even seemingly simple devices feature advanced microprocessors, and, oftentimes, MSW will not agree with these microprocessors. A PSW is the only safe choice.

For example, many devices rely on a PSW to time their operation by counting how often the wave passes through zero voltage. This works well on the smooth grid AC. But when such devices are run off an MSW inverter, their microprocessors are tricked by the MSW’s plateaus at zero voltage, which results in miscalculations of time, leading to poor performance and shorter product lifespan.

A PSW inverter, on the other hand, gives you an output that is close to identical to that of household power, which makes it perfect for any appliance that you’d normally plug into the wall. One thing to keep in mind, though, is that even normal household appliances may produce abnormal loads for short periods of time. Motors and fridges, for example, may require a significantly higher wattage during 5-15 seconds at start-up. Quality PSW inverters deal with this by having a 40%-100% surge capacity. So, when shopping for inverters, always read the specifications and make an informed choice.

In short

Modified-sine-wave inverters are relatively simple and cheap products that generally will use battery power more efficiently than pure-sine-wave inverters.

Only basic products such as normal lights bulbs and induction or shunt motors can safely be run on a modified sine wave.

Pure-sine-wave inverters require many components and therefore come at a higher cost. They produce current that is close to identical to that of grid AC, making them perfect for running sensitive electronics.

If in doubt as to whether your appliances can run on a modified sine wave, always check with the manufacturer.